Helicoverpa on Soybean
Eggs are yellow-white to brown, about 0.5 mm in diameter and are laid in clusters around floral structures and top leaves. Helicoverpa larvae can feed on soybeans at any stage of plant growth but are most likely to attack flowers and pods. They feed on tender buds, flowers and later also on pods. They bore holes into reproductive structures, feeding from inside the plant and inflicting serious damages. Small pods can be totally consumed and in large pods the larvae damage the seeds.
The aspect of the larvae varies from dark-green to reddish black depending on maturation stage and diet. The body is scattered with little black spots and ends with a dark head. At later maturity stages, lines and bands develop on their bodies. Adults are usually light brown, about 35 mm long, and have a small pale patch in the dark section of the hindwing. The factors temperature and availability of suitable host plants are most important when it comes to population regulation.
Promote populations of beneficial insects. Trichogramma wasps parasitize eggs. Microplitis, Heteropelma and Netelia wasps parasitize larvae. Predatory bugs, ants and spiders also attack the larvae. You can also apply bio-insecticides based on nucleopolyhedrovirus, spinosad and Bacillus Thuringiensis.
Always consider an integrated approach with preventive measures together with biological treatment if available. Selective insecticide treatment is the best option to rid the field from the pest without affecting beneficial insects. Use the insecticides chlorantraniliprole, flubendiamide, chlorfenapyr and acephate to reduce populations